On the honeycomb lattice, the semimetal state with Dirac nodes is stable for sufficiently small \(U\) , whereas the ground state for sufficiently large \(U\)  is a collinear sublattice antiferromagnet with opposite spin polarization on the two sublattices [1]}, [2]}. Initial simulations suggested a quantum spin liquid state at intermediate \(U\)  between the semimetal and the AF [3]}; however, the current consensus is that there is a direct continuous transition between the semimetal and AF phases with no intermediate phase [4]}, [5]}.
